The present invention relates to a shoulder rest for use with a violin or a violin-like instrument. More specifically, the invention relates to the type of shoulder rests having a relatively rigid, elongated base and upright clamping elements secured one to each end of the base. The distance between the clamping elements is adjustable to match several sizes of the body of the instrument. The adjustment of the distance between the clamping elements of the shoulder rest is effected by utilizing a row of openings provided in a foot member of at least one clamping element. The row of openings extends along the base. The openings are equidistantly spaced from each other. One or two openings are engaged with a stem-like projection or projections protruding from the top surface of the base. Thus a positive locking of the foot member is achieved, in a number of locations along the base member. In known adjustment mechanisms of this type, the number of positively locked positions is equal to or smaller than the number of the openings in the foot member. The adjacent locked positions are spaced from each other a distance equal to the spacing between adjacent openings.
The above type of adjustability of the shoulder rests has become popular because of simplicity of the structure and adjustment, its security once adjusted, and a number of sizes of violins which can be accommodated by a single shoulder rest.
A typical example of adjustable shoulder rests of this type is described, for instance, in U.S. Pat. No. 5,419,226 (Kun) issued May 30, 1995. A number of openings is provided in a foot member of each of the clamping elements at each end of the base of the shoulder rest. Another, somewhat more complex and expensive, embodiment of this principle is shown in U.S. Pat. No. 3,631,754 (Kun), issued Jan. 4, 1972.
While the adjustability of the above prior art may often be sufficient, there are applications where the spacing between adjacent openings in the foot portion is optimal for manufacture but may be too large to accommodate relatively large differences in the size of violins. This is particularly notable in the area of shoulder rests for small, children's size violins ranging from size 1/16, to 1/4. In such applications, the spacing between adjacent adjustment positions presents too large a percentage of the overall desired clamping distance due to a small size of the violins with the result that, in one position, the clamping force may be too small and in the next position excessive. Also, the length of the foot portion required to provide four adjustment positions is too much for small size violins, where space saving is of the essence.
It is also known to provide a non-positively locked adjustment of the distance between the clamping elements of a violin shoulder rest by a slide-and-setscrew arrangement such as described in U.S. Pat. No. 5,275,078 (Wolf) issued Jan. 4, 1994, where a sleeve with a setscrew receives a sliding arm supporting one of the clamping elements. On adjustment of the distance, the setscrew is tightened to secure the clamping distance. Another arrangement of a non-locked adjustment is described in U.S. Pat. No. 4,333,378 (Hrdlicka), issued Jun. 8, 1982 utilizing a longitudinal slot in the foot member and two threaded stems, projecting from the base and through the slot. Thumbnuts threaded on the stems secure the foot member (and thus the associated clamping element) to the base.
The disadvantage of the non-positively locked arrangement is that it does not provide means which would indicate inadvertent loosening of the setscrew, thumbnuts or other similar fasteners. This may result in diminished tightness of the clamping force with the possibility of accidental release of the shoulder rest from a violin while playing the instrument. The structural complexity is another disadvantage of this type of adjustment mechanism.
It is an object of the present invention to provide an improvement of the first mentioned, positively locked stem-and-opening type of adjustment which would utilize a convenient spacing between the openings in the foot portion of a support of a clamping element while at the same time allowing adjustability in a number of positions which is larger than the number of the openings in the foot portion.